/*-
 * #%L
 * HAPI FHIR OkHttp Client
 * %%
 * Copyright (C) 2014 - 2025 Smile CDR, Inc.
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */
package ca.uhn.fhir.okhttp.client;

import ca.uhn.fhir.context.FhirContext;
import ca.uhn.fhir.rest.api.Constants;
import ca.uhn.fhir.rest.api.EncodingEnum;
import ca.uhn.fhir.rest.api.RequestTypeEnum;
import ca.uhn.fhir.rest.client.api.Header;
import ca.uhn.fhir.rest.client.api.HttpClientUtil;
import ca.uhn.fhir.rest.client.api.IHttpClient;
import ca.uhn.fhir.rest.client.api.IHttpRequest;
import ca.uhn.fhir.rest.client.impl.BaseHttpClientInvocation;
import ca.uhn.fhir.rest.client.method.MethodUtil;
import okhttp3.Call;
import okhttp3.FormBody;
import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.RequestBody;
import org.hl7.fhir.instance.model.api.IBaseBinary;

import java.util.List;
import java.util.Map;

import static ca.uhn.fhir.okhttp.utils.UrlStringUtils.deleteLastCharacter;
import static ca.uhn.fhir.okhttp.utils.UrlStringUtils.endsWith;
import static ca.uhn.fhir.okhttp.utils.UrlStringUtils.everythingAfterFirstQuestionMark;
import static ca.uhn.fhir.okhttp.utils.UrlStringUtils.hasQuestionMark;
import static ca.uhn.fhir.okhttp.utils.UrlStringUtils.withTrailingQuestionMarkRemoved;

/**
 * A Http Request based on OkHttp. This is an adapter around the class
 * {@link OkHttpClient}
 *
 * @author Matthew Clarke | matthew.clarke@orionhealth.com | Orion Health
 */
public class OkHttpRestfulClient implements IHttpClient {

	private Call.Factory myClient;
	private StringBuilder myUrl;
	private Map<String, List<String>> myIfNoneExistParams;
	private String myIfNoneExistString;
	private RequestTypeEnum myRequestType;
	private List<Header> myHeaders;
	private OkHttpRestfulRequest myRequest;

	public OkHttpRestfulClient(
			Call.Factory theClient,
			StringBuilder theUrl,
			Map<String, List<String>> theIfNoneExistParams,
			String theIfNoneExistString,
			RequestTypeEnum theRequestType,
			List<Header> theHeaders) {
		myClient = theClient;
		myUrl = theUrl;
		myIfNoneExistParams = theIfNoneExistParams;
		myIfNoneExistString = theIfNoneExistString;
		myRequestType = theRequestType;
		myHeaders = theHeaders;
	}

	@Override
	public IHttpRequest createByteRequest(
			FhirContext theContext, String theContents, String theContentType, EncodingEnum theEncoding) {
		initBaseRequest(theContext, theEncoding, createPostBody(theContents, theContentType));
		return myRequest;
	}

	private void initBaseRequest(FhirContext theContext, EncodingEnum theEncoding, RequestBody body) {
		String sanitisedUrl = withTrailingQuestionMarkRemoved(myUrl.toString());
		myRequest = new OkHttpRestfulRequest(myClient, sanitisedUrl, myRequestType, body);
		addHeadersToRequest(myRequest, theEncoding, theContext);
	}

	private RequestBody createPostBody(String theContents, String theContentType) {
		return RequestBody.create(MediaType.parse(theContentType), theContents);
	}

	@Override
	public IHttpRequest createParamRequest(
			FhirContext theContext, Map<String, List<String>> theParams, EncodingEnum theEncoding) {
		initBaseRequest(theContext, theEncoding, getFormBodyFromParams(theParams));
		return myRequest;
	}

	private RequestBody getFormBodyFromParams(Map<String, List<String>> queryParams) {
		FormBody.Builder formBuilder = new FormBody.Builder();
		for (Map.Entry<String, List<String>> paramEntry : queryParams.entrySet()) {
			for (String value : paramEntry.getValue()) {
				formBuilder.add(paramEntry.getKey(), value);
			}
		}

		return formBuilder.build();
	}

	@Override
	public IHttpRequest createBinaryRequest(FhirContext theContext, IBaseBinary theBinary) {
		initBaseRequest(theContext, null, createPostBody(theBinary.getContent(), theBinary.getContentType()));
		return myRequest;
	}

	private RequestBody createPostBody(byte[] theContents, String theContentType) {
		return RequestBody.create(MediaType.parse(theContentType), theContents);
	}

	@Override
	public IHttpRequest createGetRequest(FhirContext theContext, EncodingEnum theEncoding) {
		initBaseRequest(theContext, theEncoding, null);
		return myRequest;
	}

	private void addHeadersToRequest(
			OkHttpRestfulRequest theHttpRequest, EncodingEnum theEncoding, FhirContext theContext) {
		if (myHeaders != null) {
			for (Header next : myHeaders) {
				theHttpRequest.addHeader(next.getName(), next.getValue());
			}
		}

		addUserAgentHeader(theHttpRequest, theContext);
		MethodUtil.addAcceptHeaderToRequest(theEncoding, theHttpRequest, theContext);
		addIfNoneExistHeader(theHttpRequest);
	}

	private void addUserAgentHeader(OkHttpRestfulRequest theHttpRequest, FhirContext theContext) {
		theHttpRequest.addHeader("User-Agent", HttpClientUtil.createUserAgentString(theContext, "okhttp"));
	}

	private void addIfNoneExistHeader(IHttpRequest result) {
		if (myIfNoneExistParams != null) {
			addIfNoneExistHeaderFromParams(result, myIfNoneExistParams);
		} else if (myIfNoneExistString != null) {
			addIfNoneExistHeaderFromString(result, myIfNoneExistString);
		}
	}

	private void addIfNoneExistHeaderFromString(IHttpRequest result, String ifNoneExistString) {
		StringBuilder sb = newHeaderBuilder(myUrl);
		boolean shouldAddQuestionMark = !hasQuestionMark(sb);
		sb.append(shouldAddQuestionMark ? '?' : '&');
		sb.append(everythingAfterFirstQuestionMark(ifNoneExistString));
		result.addHeader(Constants.HEADER_IF_NONE_EXIST, sb.toString());
	}

	private void addIfNoneExistHeaderFromParams(IHttpRequest result, Map<String, List<String>> ifNoneExistParams) {
		StringBuilder sb = newHeaderBuilder(myUrl);
		boolean shouldAddInitialQuestionMark = !hasQuestionMark(sb);
		BaseHttpClientInvocation.appendExtraParamsWithQuestionMark(ifNoneExistParams, sb, shouldAddInitialQuestionMark);
		result.addHeader(Constants.HEADER_IF_NONE_EXIST, sb.toString());
	}

	public static StringBuilder newHeaderBuilder(StringBuilder baseUrl) {
		StringBuilder sb = new StringBuilder(baseUrl);
		if (endsWith(baseUrl, '/')) {
			deleteLastCharacter(sb);
		}
		return sb;
	}
}
